1. Field of the Invention
The present invention relates to a height-adjustable mechanism for a running frame of a treadmill, and more particularly to such a mechanism having a gearbox and an output shaft at two sides driving a supporting rod for adjusting the height of the running frame.
2. Description of the Prior Art
A treadmill, as shown in FIG. 1, is an excellent exercise apparatus for the user to make a jogging exercise. Simply speaking, it is operated by a main motor (not shown) driving a belt (not shown) when then drives front and rear roller units so that a running belt 12 disposed around the roller units rotates. Therefore, the user can jog on the running belt in accordance with the rotation speed of the running belt 12.
In order to increase the exercise fun of the treadmill, most treadmills are fitted with a height-adjustable mechanism for adjusting the angle of elevation of the running frame 14 to different slopes. As for the height-adjusting mechanism produced by current manufacturers, it is either manually or electrically operated. The manual mechanism is inconvenient while the electric one is complicated in configuration, and therefore impractical.
It is a primary object of the present invention to provide a height-adjustable mechanism for a running frame of a treadmill which can enhance the using and operating convenience while decreasing the maintenance of the treadmill.